The paper investigates whether recent DESI BAO measurements can accommodate a negative cosmological constant (CC). Using MCMC analysis, the authors combine DESI BAO measurements with Planck CMB and Pantheon Plus datasets to explore the $w_0 w_a$CDM+CC model. The results show that the best-fit energy density of CC is $\Omega_\Lambda \sim -0.3$, which slightly improves the fitting to DESI data. Additionally, $\Omega_\Lambda = 0$ is also 1$\sigma$ consistent. The inclusion of a negative CC makes the parameters $w_0$ and $w_a$ closer to $w_0 = -1$ and $w_a = 0$, respectively. The paper discusses the implications of these findings and suggests further investigation using upcoming observations, such as JWST, to better understand the nature of dark energy and the existence of anti-de Sitter (AdS) vacua.The paper investigates whether recent DESI BAO measurements can accommodate a negative cosmological constant (CC). Using MCMC analysis, the authors combine DESI BAO measurements with Planck CMB and Pantheon Plus datasets to explore the $w_0 w_a$CDM+CC model. The results show that the best-fit energy density of CC is $\Omega_\Lambda \sim -0.3$, which slightly improves the fitting to DESI data. Additionally, $\Omega_\Lambda = 0$ is also 1$\sigma$ consistent. The inclusion of a negative CC makes the parameters $w_0$ and $w_a$ closer to $w_0 = -1$ and $w_a = 0$, respectively. The paper discusses the implications of these findings and suggests further investigation using upcoming observations, such as JWST, to better understand the nature of dark energy and the existence of anti-de Sitter (AdS) vacua.